This is the time of the year when it seems that praying mantids are everywhere. I collected this mantid today from our window screen. However, the perception that there are more mantids at this time of the season is based on the size of the mantids, not total numbers. There are actually fewer mantids at this time of the year compared to earlier in the season.
Mantids have one generation per year in Ohio. They spend the winter as eggs in a foam-like structure called an ootheca. The highest total number of mantids occurred in the spring when nymphs (immatures) hatched from the eggs. As the season progressed, total numbers steadily declined owing to nymphs becoming table fare for other predators as well as each other. Also, mantid nymphs can change their colors during each molt to match their surroundings. So, not only were they smaller than the current crop of new adults, they were also well camouflaged and more difficult to detect.
Three mantids are found in Ohio including the Carolina Mantid (Stagmomantis carolina), a native species; the European Mantid (Mantis religiosa), an introduced species, and the Chinese Mantid (Tendora aridifolia), also an introduced species. The Carolina mantid is the smallest of the three and the Chinese mantid is the largest.
Mantids are ambush predators and their meat-eating life style is personified by their specialized raptorial forelegs which are designed for grabbing and holding prey. Their common name comes from the position they hold their front legs while at rest; they look like they are praying.
Of course, it's their prey who should be praying because few victims elude death once they've felt the hug of a mantid. This includes amorous male mantids; mating isn't about hugs and kisses. Females are notorious for sometimes practicing "sexual cannibalism" meaning a femme fatale mantid may consume a male right after mating. However, it's unknown how often this actually occurs in nature; mantid males don't kiss and tell.
There are a number of mantid myths including the perception that they are effective biological control agents and the misconception that mantids are protected by state and federal laws. Mantids are not particularly effective in helping us deal with insect pests. There is usually not enough of them in one location (they're very territorial) to keep insect pest populations in check and they do not discriminate between pestiferous and beneficial insects. There are no laws protecting mantids based on their usefulness as predators or because mantid numbers are declining. Other than normal seasonal fluctuations, mantids of all species are plentiful and there are no endangered species.